Elliptic curve exponentiation apparatus that can counter differential fault attack, and information security apparatus

Abstract

Provided is an elliptic curve exponentiation apparatus that can counter the DFA when an elliptic curve exponentiation technique is used. A computation result verification unit 127 receives, as a computation result, an exponentiation-result-point (X, Y) from an elliptic curve computation unit 124. The computation result verification unit 127 computes X3+a×X+b, and computes Y2, and outputs the received exponentiation-result-point when judging that Y2=X3+a×X+b, and does not output the received exponentiation-result-point when not judging that Y2=X3+a×X+b.

Description

[0001]This application is based on an application No. 2003-018760 filed in Japan, the content of which is hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002](1) Field of the Invention[0003]The present invention relates to a computation processing technique using an elliptic curve, and in particular relates to a technique for countering Differential Fault Attack (DFA).[0004](2) Description of the Related Art[0005]Public key cryptography has conventionally been known as a method for realizing confidentiality of information, authentication of information, etc.[0006]According to public key cryptography, a pair of a secret key exclusively held by the user and a public key that is made public is generated. Encryption is performed using the public key, and decryption is performed using the secret key.[0007]Despite its large amount of computation processing, public key cryptography, which does not require a secret key to be shared by a plurality of users, is often employed in...

AI Technical Summary

Benefits of technology

"The present invention provides an elliptic curve exponentiation apparatus that can counter the DFA when using elliptic curve encryption techniques. The apparatus includes an information obtaining unit, a computation unit, a judgment unit, and an output unit. The information obtaining unit obtains a point on the elliptic curve and an exponent k smaller than a prime p. The computation unit computes the elliptic curve exponentiation of the point and the exponent k using a coefficient stored in a first storage unit. The judgment unit checks if the computed result is on the elliptic curve. The output unit outputs the result if the judgment unit determines that the result is on the elliptic curve. The apparatus can also include a second storage unit for storing a constant term coefficient that can be used to set various elliptic curves. The elliptic curve exponentiation apparatus can provide a versatile and secure solution for elliptic curve cryptography."

Problems solved by technology

However, Japanese Laid-Open Patent Application No. 2002-261751 refers to the emergence of attacks of unauthorized obtaining of secret information by analyzing various information output from an IC card or the like.

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